Trimming or clipping animal nails is a routine task of pet care. Unfortunately, it may also be a problematic ordeal, owing to the common occurrence of “cutting the quick”. The quick is the tip of the animal's digit, comprising living tissue, that extends into the animal's nail. While the nail comprises dead tissue and clipping it causes the animal no discomfort, inadvertently cutting the nail too short and also cutting the quick results in pain and bleeding for the animal, and distress for the pet owner. For animals with clear or translucent nails, it may be possible to see the quick, thereby avoiding it when cutting the nail. Many animals have one or more dark colored nails, making it nearly impossible to see the quick with the naked eye. It is nevertheless possible to use light to sense the end of the quick within the nail, and thereby position the clipper for cutting the nail without also cutting the quick.
It is therefore desirable to provide an optical source and sensor for an animal nail clipper for enabling a user to reliably position the clipper for cutting the nail without also cutting the quick. More generally, it is desirable to provide apparatus and methods for determining the location of living tissue within an animal nail for a variety of purposes related to pet grooming, pet care, and/or veterinary procedures, both diagnostic and therapeutic.